Sunday, December 13, 2009

The Science of Climate Change

The science of climate change is, as we know, complex. There are many different disciplines involved in understanding both the physics and geography of climate change as well as its impacts on people, the environment, oceans, plants and animals. No one can claim to know everything there is to know about climate and its impact.

What we are dealing with is a range of probabilities – different scenarios for the future. The Intergovernmental Panel on Climate Change (IPCC), for example, has developed a range of different scenarios for the future of the climate which in turn take into account a variety of “inputs” (data) and assumptions (models and theories) about how climate works. The IPCC does not offer predictions about the future – it has never done so. It offers some different models. Also, the IPCC, by mandate, is primarily concerned with understanding the role of man-made CO2 in the atmosphere and its impact on the climate. When it was established, the IPCC was given this mandate: to assess: “the scientific, technical and socioeconomic information relevant for the understanding of the risk of human-induced climate change” – by mandate it has a given theory of climate change.

Science is a complex enterprise in itself. It is dynamic. Scientists develop ideas which they explore and test until their ideas are robust enough to form a theory. Other scientists are attracted to one theory over other competing theories – there are always competing theories – until there is a “generally accepted view” that the science of a given aspect of our universe is understood, within the limits of currently available knowledge. But as we learn more and understand more, then formerly established theories or ideas change. It takes one compelling study with independently verified data for a currently held view to unravel. While it may take time for the former theory to decline and the new theory to emerge as the new dominant view, this is how progress occurs in science.

For example, though the precise causes of multiple sclerosis are not known, it has been generally accepted until recently that it is an autoimmune disease whereby the body attacks its own cells or tissues. In the case of MS, the target of the attack is myelin - the protective sheath surrounding the nerves in both the brain and the spinal cord. These nerves become scarred and it's this damage which interrupts the normal transmission of the central nervous system, so producing the symptoms of the disease. Some 2.5 million people worldwide have been diagnosed with MS.

In November 2009, however, a cardiologist has shifted the thinking about the disease in a radical way. Observing, from ultrasounds and MRI analysis, that all the MS patients he saw had veins that were finding it difficult to evacuate blood from the brain, leaving iron deposits in the brain, he suggested that simple surgical procedures could remedy this position and ease the symptoms of MS, if not provide the basis of a new understanding of the aetiology of MS. Dr. Paolo Zamboni, Director of the Centre for Vascular Diseases at the University of Ferrara (Italy), uses angioplasty on the veins to remove blockages and accelerate the rate at which blood circulates in the body, most especially as it is evacuated from the brain. Doing so has had major consequences for the patients he has treated. This is not to say that Professor Zamboni is right and the “consensus” is wrong, only that there is now a new framework which requires exploration since it offers both a seemingly effective treatment for some patients and a new and very different explanation of the disease.

The idea that man is the primary cause of climate change through the extensive emission of CO2 into the atmosphere is a theory of climate change - one among several. No reputable scientist disputes that climate change is occurring. The so-called sceptics differ with others as to the causes of climate change, arguing that other factors – water vapour, the sun, ocean current, el Ninio to name some – are also to be understood as factors. There are several reasons why understanding the underlying causes of climate change is important. The first is that we need a deep understanding of the dynamics of climate change so as to increase our understanding of climate: the science of climatology, which is in its infancy, needs a robust and evidence based understanding of climate dynamics. The second is more about public policy – if the current dominant theory is correct and CO2 is the primary cause of climate change, then we can act to reduce CO2 emissions and “de-carbonize” our economies. The problem is that doing so changes our economies in fundamental ways and requires massive investments and multilateral political action globally – both difficult to achieve. There is a third reason why this debate between man made vs other explanations is important, which is to inform our understand of the link between science and public policy.

Roger Pielke Snr., a well established scientist who has worked extensively on the climate change file, has suggested that there are basically three core hypothesis at play in the scientific community engaged in work on climate science. These are:

The Total Sceptic Position: Human influence on climate variability and change is of minimal importance, and natural causes dominate climate variations and changes on all time scales. In coming decades, the human influence will continue to be minimal.

The Emerging Position: Although the natural causes of climate variations and changes are undoubtedly important, the human influences are significant and involve a diverse range of first- order climate forcings, including, but not limited to, the human input of carbon dioxide (C02). Most, if not all, of these human influences on regional and global climate will continue to be of concern during the coming decades.

The IPCC Position: Although the natural causes of climate variations and changes are undoubtedly important, the human influences are significant and are dominated by the emissions into the atmosphere of greenhouse gases, the most important of which is C02. The adverse impact of these gases on regional and global climate constitutes the primary climate issue for the coming decades.

The claim by many is that the “science is settled”, by which they mean it is settled around the IPCC position. This claim is based on all sorts of evidence, some of it very scant. Foe example, it is claimed that 4,000 scientists agreed with the IPCC fourth assessment report released in 2007. This is a fabrication. Some 4,000 people, around 2,580 scientists, were asked to contribute or review materials for the assessment. Not all agreed with the assessment – in fact, one quarter of reviewers made negative comments about the sections they reviewed. We do not in fact know how many scientists agree with the IPCC assessment – the question was never actually asked.

The reality is that most of the peer reviewed scientific literature favours the emerging position over the IPCC position. It is also the case that very little of the literature favours the sceptic position (though it is worth noting that some does and it comes from respected figures in physics and climatology).

Scientific analysis therefore needs to take into account and give more serious consideration to the other factors that have a bearing on climate change. These include the role of oceans as “sinks” for CO2, the role of ocean currents, naturally occurring events (earthquakes, hurricanes, volcanic eruptions), the sun and sun spots, other green house gasses (especially water vapour), the tilt of the earth and so on. All are know to have some impact.

By focusing on CO2 and the IPCC theory, the public policy is based then on what is known as the precautionary principle. While most scientists recognize that the sources of climate change are complex but that CO2 is an influencing factor, the public policy we are asked to adopt is that it is a sufficiently significant factor for us to act to reduce its impact on what are perceived as negative risks from climate change (there are benefits of climate change also to be considered).

Thomas Friedman, writing in the New York Times, captures this issue succinctly. He observes:

What we don’t know, because the climate system is so complex, is what other factors might over time compensate for that man-driven warming, or how rapidly temperatures might rise, melt more ice and raise sea levels. It’s all a game of odds. We’ve never been here before. We just know two things: one, the CO2 we put into the atmosphere stays there for many years, so it is “irreversible” in real-time (barring some feat of geo-engineering); and two, that CO2 buildup has the potential to unleash “catastrophic” warming.

When I see a problem that has even a 1 percent probability of occurring and is “irreversible” and potentially “catastrophic,” I buy insurance. That is what taking climate change seriously is all about.

He is not suggesting that the science is settled, only that the two dominant hypothesis about climate change both have CO2 as a significant factor. Friedman goes on, however, with this:

If we prepare for climate change by building a clean-power economy, but climate change turns out to be a hoax, what would be the result? Well, during a transition period, we would have higher energy prices. But gradually we would be driving battery-powered electric cars and powering more and more of our homes and factories with wind, solar, nuclear and second-generation biofuels. We would be much less dependent on oil dictators who have drawn a bull’s-eye on our backs; our trade deficit would improve; the dollar would strengthen; and the air we breathe would be cleaner. In short, as a country, we would be stronger, more innovative and more energy independent.

But notice that science is not suggesting these actions, only that CO2 is a factor and that action to reduce CO2 may (a fifty-fifty chance if the reductions are severe enough) have an impact on the climate. Science is the back-cloth to public policy, not the driver. Climatologists have nothing to say about the extent of “reparations needed by developing nations to compensate them for slower growth and decarbonising the growth they do have – that is a political and economic question.

Economics is a science, requiring artistic license. The economic analysis of alternative energy sources, biofuels and clean energy regimes is an important feature of our understanding of adaptability to climate change. But psychology is also important – another science – in helping us understand why individuals do or do not act to decarbonise their own life styles and that of their communities (a sociological question). The leveraging of these sciences in furthering our understanding of adaptive processes has yet to take place – they have not had the benefit of the $9 billion global annual R&D expenditure on climate change. It is time they got a larger slice of the pie.

If the emerging hypothesis is also better understood, more of our effort needs to go into understanding the dynamic relation between all of the variables associated with climate change, not just a select few. The climate models on which many of the IPCC scenarios are based are in their early stages of maturation. It is time for new energy and a broader base of scientists to be engaged in developing them further.

Very few areas of science are ever settled – so called “closed” areas of science – almost all areas of science are open to debate, conjecture, new analysis. The secret to good science is transparency, quality analysis (including excellent statistical techniques, sometime lacking in the climate science – e.g. the “hockey stick” of Michael Mann), openness to debate and challenge and a respect between scientists. The recent Climategate emails suggest that these principles of good science have not always been the benchmark used by those who should know better. But we should not let Climategate distract from the task of understanding what is happening, why and for this to help us better understand what we can do.

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